代码语言:txt 复制 const email = 'example@example.com'; User.findOne({ email }, (err, user) => { if (err) { console.error(err); } else if (user) { console.log('该email已存在'); } else { const newUser = new User({ email, name: 'John Doe' }); newUser.save((err, saved...
选择2可能是最干净的。假设您有一个名为conn的MongooseConnection对象，该对象已使用mongoose.create...
(400).json({message:"Can not perform find operation.", error: error }); } //if user exists if (user.length) { //check password if (user.password === password) { //assign jwt, redirect } else { //"username/password is incorrect" } } else { //"username/password is incorrect" ...
选择2可能是最干净的。假设您有一个名为conn的MongooseConnection对象，该对象已使用mongoose.create...
$elemMatch可与嵌入式文档数组一起使用：在您的情况下，您可以尝试：
在底层，MyModel.exists（{ answer：42 }）等同于MyModel.findOne（{ answer：42 }）.select（{ _id...
Have age (IF EXISTS) between the primary doc age preference and primary doc have age (IF EXISTS) between the foreign doc preference (i.e two-way check)My attempt is the following but has two issues:$exists can't be used inside $expr idk why Age query is one way right now...
"Operation Mongoose" is a two-part episode, comprising the twenty-first and twenty-second episodes of Once Upon a Time. It was written by Edward Kitsis and Adam Horowitz. It is the final episode of the fourth season, and premiered on May 10, 2015. The to
{ $cond: { if: { $in: [`$$${field.fieldName}`, ['', null]] }, then: [], else: `$$${field.fieldName}`, }, }, In this condition, I also want to check the field.fieldName exits. $exists: true, then it will something like if ( !filed.fieldName || field.fieldName ...
在TypeScript 中,Mongoose 是一个用于在 Node.js 环境下操作 MongoDB 数据库的对象模型工具。Mongoose 提供了一些静态方法,用于在模型层级上执行一些常见的数据库操作。 Mongoose 的静态方法可以通过模型对象直接调用,而不需要实例化模型。下面是一些常用的 Mongoose 静态方法及其解释:...